Dental impression tray



May 11 1926.

I s. HOLLANDER ET AL DENTAL IMPRESSION TRAY Filed Nov. 16, 192:5 V

atented May ll, i926.

UNITED STATES a so s lmioofizio SAMUEL HOLLANDER AND EDWARD I. WEISBERG, OF CLEVELAND, OHIO.

DENTAL IMPRESSION TRAY.

Application filed November 10, 1923.

The objects of the invention are to provide an improved form of dentists impression tray in which a plaster cast or mold can be made of the teeth and gums of a patient, and which is at the same time partially divided on lines permitting it to be readily separated for removal from the teeth and gums, in unbroken accurate sections, without breaking or crumbling the parts. Hitherto no indication has been made in a one piece tray of definite lines of parting of the cast to be made therefrom.

The device comprises, a tray formed in one integral piece, and provided with suitably spaced integral inwardly projecting ridges, which form grooves in the plaster cast, and locate positions where the cast can be separated into definite parts, with a minimum amount of cutting into the plaster.

By this means,the impression of all undercuts and depressions in the teeth can be obtained, and yet the portions of the cast can be readily separated from each other and from the teeth and gums while the cast is in the mouth of the patient, without breaking away or crumbling the edges of any portion of the cast.

The device also includes a hollow sheet metal tray of the usual form provided with longitudinally and centrally disposed acute ridges in its bottom wall that extend on each side from the rear towards the curved front portion thereof, and terminate in similar transverse ridges extending up the sides of the tray. Also a horizontal inwardly extending ridge is formed in both the lower and upper trays across the front wall of each tray, at substantially the same elevation as the projecting edges of said longitudinal ridges and merges at its ends in the trans verse ridges. The transverse and longitudinal ridges are preferably formed at an acute angle to facilitate the parting of the cast.

By means of this construction, longitudi- 1 nal and transverse grooves or markers are formed in the cast taken from the tray at definite points, and at these points the cutting tool can be inserted and the matrix or cast can be readily split or cut away in such a manner that it will come away from the gums and teeth after it has become set and hardened.

By means of the horizontal angular ridge a transverse groove is formed in the outer face of the cast or matrix, which permits the insertion of a tool horizontally therein while Serial No. 673,943.

the cast is in the mouth of the patient, so as to sever the parts on a horizontal line in such a manner that the front of the cast can be readily detached from the rear and bottom portions thereof and from the teeth and gums.

These longitudinal and transverse ridges also serve as means for locating the tray in the mouth of the patient, and may make direct contact with the teeth without affect ing in any way the perfection of the cast. For instance, the longitudinal ridges may bisect the bi-cuspids and molars in the rear of the mouth, and the transverse ridges may bisect the cuspids.

In this manner, large sections of the plaster cast can be removed with facility, regardless of the shape or position of the teeth in the dental arch.

Also the sections can be accurately assembled, since the teeth will serve as guides for locating the tray in the month. In this manner, the device provides, a method of more accurately obtaining the plaster impressions.

Further, the plaster cast will be strengtl'iened at intermediate points to prevent it from breaking.

A further. advantage lies in the integral construction of the tray, since if the tray were made in sections, one or more sections might be mislaid, and the device would not be useful, also time would be lost in finding and assembling them, further a number of separate parts could not always be accurately assembled to make a perfect cast.

The invention is hereinafter more fully disclosed, illustrated in the accompanying drawings, and specifically pointed out in the claim.

In the accompanying drawings, Fig. 1 is a plan of the tray for taking an impression of the lower jaw, Fig. 2 is a longitudinal section thereof, Fig. 3 is a transverse section on line 11, Fig. 1.

Fig. 4 is a plan of the tray for taking an impression of the upper jaw. Fig. 5 is a perspective of the plaster cast taken from the lower tray. Fig. 6 is a plan of a partial or sectional tray.

In these views 1 is the tray having a ClllWBCl front, and rearwardly and tending sides, 2, 2 are acute angle ridges formed longitudinally in the bottoms of the rear portions of the tray, and registering with the bicuspids and molar teeth, 3, 3 are similar transverse ridges which separate the curved front portion of the tray from the said rear portions, and are preferably positioned to register with the cuspid teeth.

The curved front wall is provided with an angular horizontal inwardly extending angular ridge 5, which .provides an angular groove 6 across the front of the cast. In this angle a scraping tool can be readily inserted to divide the curved portions into inner and outer parts on a line with the upper edges of the "front teeth, thus facilitating the remo *al of the cast therefrom.

Also, the longitudinal and transverse grooves thus formed in the rear portions of the cast. indicate positions at which the rear portions may be readily divided into large accurately formed sections that can be easily removed from the teeth and gums, without discomfort to the patient, and without danger of breaking the parts or crumbling the edges.

In Fig. 4 the tray for taking the impression of the upper aw is shown. which differs from the other tray only in employing shorter transverse ridges.

In Fig. 5 a perspective of a cast C from the lower tray is shown and the positions of the longitudinal grooves G and transverse grooves H, and horizontal front recess 1, are shown.

It will be seen that the grooves partially divide the cast and greatly facilitate the separation of the cast into sections that will readily come away from the mouth since they may extend to or nearly to the crowns of the teeth.

In Fig. 6 a partial tray J is shown which isrevolvable at K upon a handle L; thus permitting it to be used upon either side of the mouth. This tray is substantially arouate in shape and'composed of a curved center M and short linear extremities N, N.

This improved impression tray has the great advantage over trays made in separate portions fitted together that the lines of division are always accurately formed, and

produce uniformly accurate castings that will not have connected edges, so that they will require the minimum amount of touching up afterwards. This fact greatly facilitates reproduction ot the mold'sulosequently from any material and prevents multiplication of errors therein.

Having described the invention What we claim as new and desire to secure by Letters Patent is p In a dental impression tray, a longitudinally channelled tray body having a curved front portion and integral elongated rear portions, said rear portions being provided with inwardly projecting acute angled longitudinal ridges on their bottom walls, spaced similar transverse ridges across said rear portions merging in said longitudinal ridges, the front wall of said tray being provided with a horizontal inwardly projecting ridge the extremities of which merge into said transverse ridges, said ridges being positioned on the lines of division of the cast to be subsequently formed in said tray.

In testimony whereof, we hereunto set our hands this 8rd day of November, 1923.

SAMUEL HOLLANDER. EDVVARDI. TVEISBERG. 

